Generally, the configuration and design of a container affects the level to which end consumers, as well as bottlers, manufacturers, distributors, shippers, and retailers, hereinafter referred to collectively as “the bottling industry,” are satisfied with a container. Aluminum bottles offer the bottling industry and consumers many benefits. Aluminum bottles provide ideal surfaces to decorate with brand names, logos, designs, product information, and/or other preferred indicia and thus offer bottlers, distributors, and retailers an ability to stand out at the point of sale. Aluminum bottles have a strength-to-weight ratio advantage which enables higher stacking than comparable glass bottles. The increased durability of aluminum bottles also reduces the number of containers damaged during processing and shipping, resulting in further savings. Additionally, aluminum bottles are lighter than glass bottles resulting in energy savings during shipment. Finally, recycling aluminum bottles is easier because labels and other indicia are printed directly onto the aluminum bottles while glass and plastic bottles typically have labels that must be separated during the recycling process.
Aluminum beverage bottles are particularly attractive to consumers because of the convenience they offer. The light weight of aluminum bottles makes them easier to carry. Aluminum bottles are particularly suitable for use in public places and outdoors because they are durable, safe, and give effective protection from light and air which may negatively affect the quality and taste of the beverage contained in the aluminum bottle. In addition, aluminum bottles cool down faster than beverage containers made of other materials resulting in colder beverages faster. Glass bottles do not offer the same convenience because they are heavier than aluminum bottles and are easier to break. Further, some public facilities and parks prohibit glass bottles because they pose a safety risk when broken.
Aluminum beverage bottles are known in the container industry and may be formed using an impact extrusion process. Impact extrusion is a process utilized to make metallic containers and other articles with unique shapes. The products are typically made from a softened metal slug comprised of steel, magnesium, copper, aluminum, tin, and lead and other alloys. The container is formed inside a confining die from a cold slug which is contacted by a punch. The force from the punch deforms the metal slug around an outer diameter of the punch and the inner diameter of the confining die. After the initial shape is formed, the container or other apparatus is removed from the punch with a counter-punch ejector, and other necking and shaping tools are used to form the device to a preferred shape.
In a conventional impact extrusion process, almost pure or “virgin” aluminum is used due to its unique physical characteristics, and is commonly referred to as “1070” or “1050” aluminum which is comprised of at least about 99.5% of pure aluminum. Current commercial impact extruded (IE) containers made with a 1070 or 1050 aluminum alloy are very soft and have low mechanical properties and thus require thick walls. IE containers for aerosols and other pressure vessels require high strength and thus use thicker gage and heavier materials than traditional aluminum beverage containers. Because of the thickness and strength requirements of these containers, the cost to manufacture the containers may be significantly higher than the cost to manufacture conventional metal beverage containers which generally utilize 3104 aluminum alloy. The thickness of traditional IE containers also makes the manufacture of integral threads more complex. Further, the soft nature of aluminum alloy used for traditional IE containers is too soft to form integral threads which are sufficiently strong to close with a threaded closure such as a roll on pilfer proof (ROPP) closure. Tests of integral threads formed on IE bottles manufactured from standard alloys show that the threaded area will collapse at a substantially lower load force compared to the threads of a container made through a draw and ironing process.
The manufacture of drawn and ironed (D&I) aluminum containers using 3104 aluminum alloy results in a considerable amount of scrap aluminum material. The scrap aluminum is typically collected and recycled. However, in the past, conventional impact extrusion alloys were not hard or strong enough to be used to form IE containers with a threaded neck. Using a percentage of scrap aluminum from the D&I process blended with conventional impact extrusion alloys could produce a sufficiently strong threaded container from impact extrusion that would result in material cost savings for bottling industry and reduce the environmental footprint of the threaded container.
To meet the need of an IE beverage container with a thread for a ROPP closure, the commercial container industry typically attaches threads to the neck of an IE beverage container after the container has been formed. These external threads are usually made of plastic or metal and in some cases are known as “outserts.” These external threads have several shortcomings, including increased cost, complexity of the manufacturing process, and adverse capping performance characteristics including caps spinning on the container neck and container leaking around the cap and/or outsert. Thus, there is a significant need for an IE aluminum container which is comprised of recycled aluminum content which is sufficiently hard and rigid to allow for the formation of a threaded neck to receive a selectively removable closure such as a ROPP closure.